Investigation of change regularity of energy states of Mn²⁺ in halides

Data on ⁴E, ⁴A₁ (⁴G) and ⁴T₁ (⁴G) energy states of Mn²⁺ ion in some halides have been obtained and analyzed. With use of the dielectric theory of the chemical bond for complex crystals, several chemical bond parameters were calculated. The change regularity of the energy states of Mn²⁺ in halides has been studied. The results show that the covalence, the coordination number and the radius of the central ion are the main factors influencing the energy states of Mn²⁺ ion in halides. The relationships between these factors and the energy state ⁴T ₁ (⁴G), the energy difference ΔE (ΔE= ⁴E, ⁴A₁ (⁴G)→⁴T ₁ (⁴G)) of Mn²⁺ ion in halides were established: E=2.0898+0.8618 exp (-F/0.2431); ΔE=0.3201+0.9713F. These relationships allow us to predict the position of energy state ⁴T₁ (⁴G) and the energy difference ΔE of Mn²⁺ in halides. This work can be significant for further understanding the luminescent properties of Mn²⁺ and can be used to develop new Mn²⁺-doped phosphors.